US20190058566A1 - System and method of ue-centric radio access procedure - Google Patents

Abstract

A method and system for operating a user equipment (UE) wherein a first set of radio access procedures are supported when the UE is in a first operating state, and a second set of radio access procedures are supported when the UE is in a second operating state.

Description

RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 15/165,985, filed May 26, 2016; which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 62/168,658, filed May 29, 2015; the contents of both of which are incorporated herein by reference.
FIELD
• The present disclosure relates to a system and method for wireless communications, and in particular, to a system and method for user equipment centric radio access procedures.
BACKGROUND
• Wireless networks that support mobile user equipment (UE) are generally cellular in nature. The Radio Access Network (RAN) of a wireless network provides radio access to a UE using a plurality of base stations that each have a corresponding coverage area, also known as a coverage cell or cell. Each base station supports communications the UEs within its corresponding cell. Each UE is assigned a cell-specific ID which is locally unique. The performance of cell-centric networks is limited by factors such as inter-cell interference and non-uniform spectral efficiency across a cell.
SUMMARY
• Wireless networks may employ radio access virtualization (RAV) that will eliminate traditional cell boundaries in favor of user equipment (UE) centric resource assignment. RAV can include a number of different components that will use different procedures in different UE operational states. Example embodiments are described herein for supporting selected RAV procedures in various UE states. In example embodiments there is described a method and system for operating a UE wherein a first set of radio access procedures are supported when the UE is in a first operating state; and a second set of radio access procedures are supported when the UE is in a second operating state. According to one example aspect is a method for operating a user equipment device that is enabled to transition between at least a first operating state that supports a first set of radio access procedures and a second operating state that supports a second set of radio access procedures. The method includes performing an initial access procedure, while the user equipment device is in the first operating state, to establish a first set of radio access parameters for the user equipment device to use while in the first operating state and a second set of radio access parameters for the user equipment device to use while in the second operating state. The method further includes transitioning from the first operating state to the second operating state and transmitting using the second set of radio access parameters.
• In some example configurations, establishing the first and second sets of radio access parameters includes receiving the first and second sets of radio access parameters at the user equipment device from a wireless network entity. In some examples, the radio access parameters include a user equipment identifier for the user equipment device to use in both the first operating state and the second operating state. In some configurations, the first set of radio access parameters includes a user equipment sounding reference signal and a sounding channel resource assignment for the user equipment device, and the second set of radio access parameters includes a user equipment identifying sequence and an uplink tracking channel resource assignment for the user equipment device.
• In some examples the method includes periodically transmitting from the user equipment device, while in the first operating state, the user equipment sounding reference signal using the sounding channel resource assignment, and transmitting from the user equipment device, while in the second operating state, the user equipment identifying sequence using the uplink tracking channel resource assignment. In some configurations, the periodic transmission of the user equipment identifying sequence requires less wireless network resources than the periodic transmitting of the user equipment sounding reference signal.
• In some examples, the method includes monitoring, at the user equipment device, for downlink grant-free transmissions in both the first operating state and the second operating state. In some examples, the method includes sending, from the user equipment device, uplink grant free transmissions in both the first operating state and the second operating state.
• In some examples, the method includes, at the user equipment device, transitioning from the second operating state to the first operating state upon receiving a message on a data downlink channel monitored by the user equipment device that there is downlink data for the user equipment device requiring that the user equipment device transition from the second operating state to the first operating state, and then receiving the downlink data while in the first operating state. In some examples, the message includes a unicast message that includes an identifier for the user equipment device and a flag indicating that a state transition is required.
• In some examples aspects, a user equipment device for operating in a wireless network is configured to perform the above methods. For example, one aspect provides a user equipment device for operating in a wireless network, the user equipment device including a wireless network interface for sending and receiving radio frequency signals through the wireless network, a processor coupled to the wireless network interface, and a memory coupled to the processor. The memory stores executable instructions that, when executed by the processor, enable the user equipment device to: transition, upon the occurrence of predetermined events, between a first operating state that supports a first set of radio access procedures and a second operating state that supports a second set of radio access procedures; and perform an initial access procedure, while the user equipment device is in the first operating state, to establish a first set of radio access parameters for the user equipment device to use while in the first operating state and a second set of radio access parameters for the user equipment device to use while in the second operating state.
• In some aspects, the user equipment device is configured to establish the first and second sets of radio access parameters by receiving the network access parameters at the user equipment device from a network entity through the wireless network. In some aspects, the radio access parameters includes a user equipment identifier for the user equipment device to use in both the first operating state and the second operating state. In some configurations, the first set of radio access parameters includes a user equipment sounding reference signal and a sounding channel resource assignment for the user equipment device, and the second set of radio access parameters includes a user equipment identifying sequence and an uplink tracking channel resource assignment for the user equipment device.
• In some examples, the user equipment device is configured to: periodically transmit from the user equipment device, while in the first operating state, the user equipment sounding reference signal using the sounding channel resource assignment; and periodically transmit from the user equipment device, while in the second operating state, the user equipment identifying sequence using the uplink tracking channel resource assignment. The periodic transmission of the user equipment identifying sequence requires less wireless network resources than the periodic transmitting of the user equipment sounding reference signal.
• In some examples, the user equipment device is configured to provide always on-connectivity through the wireless network interface in both the first and second operating states by: sending the user equipment sounding reference signal using the sounding channel resource assignment in the first operating state but not the second operating state; and sending the user equipment identifying sequence using the uplink tracking channel resource assignment while in the second operating state; support grant-free uplink and downlink transmissions for data below predefined thresholds in both the first operating state and the second operating state; and monitor a downlink data notification channel while in the second operating state for an indication to transition to first operating state.
• According to some example aspects is a network element for operating in a wireless network. The network element includes a wireless network interface for sending and receiving radio frequency signals through the wireless network to one or more user equipment devices; a processor coupled to the wireless network interface; and a memory coupled to the processor. The memory stores executable instructions that, when executed by the processor, enable the network element to: perform an initial access procedure to provide network access parameters to a user equipment device that is operating in a first operating state, the network access parameters including: a user equipment identifying sequence and an uplink tracking channel resource assignment for the user equipment device to use while in a second cooperating state; and a user equipment sounding reference signal and a sounding channel resource assignment for the user equipment device to use while in the first operating state.
BRIEF DESCRIPTION OF THE DRAWINGS
• Reference will now be made, by way of example, to the accompanying drawings which show example embodiments of the present disclosure, and in which:
• FIG. 1 illustrates an example of a UE-centric wireless communications system according to example embodiments.
• FIG. 2 is a block diagram that illustrates different user equipment operating states and the functions and procedures associated with those states according to example embodiments.
• FIG. 3 is a block diagram that illustrates an example of an initial access procedure that is supported in an active state according to example embodiments.
• FIG. 4 is a block diagram that illustrates an example of a network side actions enabled by a network controller for Uplink (UL) grant-free transmissions in multiple operating states.
• FIG. 5 is a block diagram that illustrates an example of the actions performed by User Equipment (UE) for UL grant-free transmissions in multiple operating states.
• FIG. 6 is a block diagram that illustrates an example of network side actions enabled by the network controller for downlink (DL) grant-free transmissions in multiple operating states.
• FIG. 7 is a block diagram that illustrates an example of the actions performed by UE for DL grant-free transmissions in multiple operating states.
• FIG. 8 is a block diagram that illustrates an example of UE functions that are performed by a UE for uplink communications in a first operating state.
• FIG. 9 is a block diagram that illustrates an example of UE functions that are performed by a UE for downlink communications in a first operating state.
• FIG. 10 is a block diagram that illustrates an example of Network-Oriented Measurement Procedures performed for a UE in the first operating state.
• FIG. 11 is a block diagram that illustrates an example of a network initiated second (ECO) state to first (Active) state transition procedure fora UE.
• FIG. 12 is a block diagram that illustrates an example of a UE initiated second (ECO) state to first (Active) state transition procedure.
• FIG. 13 is a block diagram that illustrates an example of a state transition procedure for moving from UE first (Active) state to a UE second (ECO) state.
• FIG. 14 is a block diagram that illustrates an example of a UE tracking procedure performed when the UE is in the second (ECO) state.
• FIG. 15 is a block diagram that illustrates an example of a DL Data notification procedure performed when the UE is in the second (ECO) state.
• FIG. 16A illustrates a block diagram that shows a power-off deregistration procedure.
• FIG. 16B illustrates a block diagram that shows a registration timer expiry deregistration procedure.
• FIG. 17 is a block diagram of a processing system that may be used for implementing devices in the system ofFIG. 1 according to example embodiments.
• Similar reference numerals may have been used in different figures to denote similar components.
DESCRIPTION OF EXAMPLE EMBODIMENTS
• FIG. 1 illustrates awireless communications network100 to which the radio access procedures described herein can be applied. Systems and methodologies for implementing UE-centric communications networks can be found, for example, in the disclosures of the following documents, the contents of which are incorporated herein by reference: (1) U.S. patent application Ser. No. 14/550,362 filed Nov. 21, 2014 (publication number US 2015/0141002 A1), entitled: “System and Method for Non-cellular Wireless Access”; (2) U.S. patent application Ser. No. 13/974,810 filed Aug. 23, 2013 (publication number US 2014/0113643 A1), entitled “System and Method for Radio Access Virtualization”; (3) U.S. patent application Ser. No. 13/930,908 filed Jun. 28, 2013 (publication number US 2015/0003263 A1), entitled “System and Method for Network Uplink Measurement Based Operation Using UE Centric Sounding”; (4) U.S. patent application Ser. No. 14/150,539 filed Jan. 8, 2014, entitled “System and Method for Always On Connections in Wireless Communications System” (publication number US2015/0195788 A1)); (5) U.S. Patent Application No. 62/141,483 filed Apr. 1, 2015, and Ser. No. 15/009,626 filed Jan. 28, 2016 entitled “System and Method for a Tracking Channel”; (6) U.S. patent application Ser. No. 13/608,653 filed Sep. 10, 2012 (publication number US 20140073287 A1), entitled “System And Method For User Equipment Centric Unified System Access In Virtual Radio Access Network”; (7) U.S. patent application Ser. No. 14/609,707 filed Jan. 30, 2015, entitled “Apparatus And Method For a Wireless Device To Receive Data in an Eco State”; (8) U.S. patent application Ser. No. 13/911,716 filed Jun. 6, 2013 (publication number US 2014/0192767 A1), entitled “System and Method for Small Traffic Transmissions”; and (9) “U.S. patent application Ser. No. 13/790,673 filed Mar. 8, 2013, (publication number US 2014/0254544 A1) System and Method for Uplink Grant-Free Transmission Scheme”.
• As described in the documents noted above, in example embodiments UE-centricwireless communications network100 organizes network communications around a user equipment dedicated connection ID (UE DCID) associated with a User Equipment (UE) device. In this regard,wireless communications network100 employs an air interface design to support non-cellular based wireless access.
• In an example embodiment,wireless communications network100 ofFIG. 1 includes a plurality of transmission reception points (TRPs)102 andUEs104, and a cloud processor orcontroller106 in communication with theTRPs102. TheTRPs102 may include any component capable of providing wireless access by establishing uplink and/or downlink connections with theUEs104, such as a base transceiver station (BTS), a NodeB, an evolved NodeB (eNodeB or eNB), a femtocell, and other wirelessly enabled network node devices. TheUEs104 may comprise any component capable of establishing a wireless connection with theTRPs102. TheTRPs102 may be connected tocontroller106 via a backhaul network (not shown). The backhaul network may be any component or collection of components that allow data to be exchanged between theTRPs102 and thecontroller106 and/or a remote end (not shown). In some embodiments, thewireless communications network100 may comprise various other wireless devices, such as relays, femtocells, etc. Thecontroller106 may be any type of data processing system capable of performing the processes disclosed below and capable of communication with other devices.
• In one example ofwireless communications network100, theTRPs102 are not associated with a cell. Rather, thecontroller106 organizes theTRPs102 intological entities110. EachUE104 is assigned to alogical entity110 and is assigned a unique UE dedicated connection ID (UE DCID). In an embodiment, theUE104 can be a mobile phone, a sensor, a smart phone, or other wireless device. TheUE104 may move freely within a service area of a singlelogical entity110 without acquiring a new UE DCID. EachTRP102 monitors signal strengths for anyUE104 detectable by theTRP102 and sends this data to thecontroller106.Controller106 can both create and manage the membership oflogical entity110. When aUE104 initially attaches to the network,controller106 can createlogical entity110 and assign a set ofTRPs102 tological entity110. This assignment can be done in accordance with measurements of the received strength of the UE transmission at theTRP102. As the conditions in the network change, or as the UE moves through the network,controller106 can modify the membership oflogical entity110. This determination can be performed dynamically in some embodiments. In some examples, thecontroller106 assigns a logical entity ID to thelogical entity110 and assigns a UE DCID to eachUE104 according to the logical entity ID to which theUE104 is assigned and a user equipment identifier (UE ID) of theUE104. In some embodiments, the UE ID is a unique identifier permanently or semi-permanently assigned to a device, for example when the UE device is manufactured, or delivered to a network operator, or assigned to a user. In some examples, the UE DCID is a combination of the UE ID and the logical entity ID.
• The UE DCID is used by theUE104 when transmitting, and may also be used when receiving. In some examples, thecontroller106 selects one or more of theTRPs102 from the group ofTRPs102 in thelogical entity110 to provide radio access to theUE104. In an embodiment, thecontroller106 selects theTRP102 based on relative signal strengths of theUE104 at each of theTRPs102 in thelogical entity110 and/or the loads of eachTRP102 in thelogical entity110. In other embodiments, other selection criteria can be utilized. In an embodiment, thecontroller106 dynamically reassigns anew TRP102 in thelogical entity110 to serve theUE104 based on changes to the signal strength of the104 UE at eachTRP102 in thelogical entity110. The change in signal strength may be due to UE mobility or to other factors.
• In an embodiment, thecontroller106 can enable or disable the participation of one ormore TRPs102 in alogical entity110 to reach a tradeoff between the service quality provided to all coveredUEs104 and energy saving criteria.
• In an embodiment, theTRPs102 assigned to alogical entity110 may be changed dynamically by thecontroller106 according to changes in network conditions.
• In example embodiments, thewireless communications network100 is configured to support different operating states forUE104, with each operating state supporting different UE functionality. In this regard,FIG. 2 is a block diagram that illustratesdifferent UE104 operating states and the functions and procedures associated with those states according to example embodiments. In particular, in one example theUE104 is configured to implement astate machine200 that can transition between two different states, namely a first “Active”state204 and a second, energy economizing, “ECO”state202. In example embodiments, a reduced set of UE functionality is supported in theECO state202 compared to the Active state. At least some degree of connectivity towireless communications network100 is supported in both states, such thatUE104 maintains an always-on connection to thewireless communications network100. Examples of the implementation ofstate machine200 onUE104 are described in detail in the aforementioned documents entitled “System and Method for Always On Connections in Wireless Communications System” publication number US2015/0195788 A1 and “Apparatus And Method For a Wireless Device To Receive Data in an Eco State” U.S. patent application Ser. No. 14/609,707. In example embodiments, more than two operational states can be supported, with each state providing a different level of device functionality and requiring different levels of network resources.
• In the example ofFIG. 2, a first set of radio or network access functions or procedures, referred to herein asActive procedures208, is supported inActive state204 and a second set of radio or network access functions or procedures, referred to herein asECO procedures206, is supported inECO state202. As will be explained in greater detail below, in at least some embodiments somecommon procedures207 are supported in both states, however some procedures are exclusive to one or the other of theActive state204 or theECO state202. Furthermore, the procedures shown inFIG. 2 are not an exhaustive list of all the functionality supported in either state.
• In the illustrated embodiment, the followingActive procedures208 are supported exclusively in the Active state204:
• • Initial Access Procedures210
  • ScheduledTransmission Procedure214
  • Network-orientedMeasurement Procedure216
• In the illustrated embodiment, the followingECO procedures206 are supported exclusively in the ECO state202:
• • Down Link (DL)Data Notification Procedure224
  • Tracking Procedure222
• In the illustrated embodiment, the followingcommon procedures207 are supported in both theActive state204 and the ECO state202:
• • Grant-free Transmission Procedure212
  • Deregistration Procedure226
• In the illustrated Embodiment, the following procedures enable transition between theActive State204 and the ECO state201:
• • ECO toActive Procedures218
  • Active toECO Procedures220
• Each of the above procedures will now be explained in greater detail with reference toFIGS. 3-16.
• FIG. 3 illustrates an example of aninitial access procedure210 that is supported byUE104 in theActive state204.Initial access procedure210 will be performed whenUE104 is attempting to establish contact with thewireless communications network100, for example when theUE104 is being powered on.Initial access procedure210 is used to establish sets of network access parameters that will be used byUE104 in various operating states. Aspects of suitable initial access procedures are described in detail in the aforementioned documents (see for example U.S. patent application Ser. No. 14/550,362 filed Nov. 21, 2014 (publication number US 2015/0141002 A1), entitled: “System and Method for Non-cellular Wireless Access”; and U.S. patent application Ser. No. 13/974,810 filed Aug. 23, 2013 (publication number US 2014/0113643 A1), entitled “System and Method for Radio Access Virtualization”). AccordinglyFIG. 3 and the accompanying description provide a high level overview.
• As shown inFIG. 3,initial access procedure210 includes the following actions:UE104 searches for a synchronization signal associated with a TRP102 (Hypercell ID) (Action300);UE104 accesses thewireless communications network100 via a pre-defined default frame structure (Action302);UE104 obtains DL synchronization via a synchronization (sync) channel (Action303);UE104 uses Physical Random Access Channel (PRACH) for initial access (Action304); and the network authenticatesUE104 and assigns a UE dedicated connection ID (UE DCID). More particularly, with respect toActions300 to303, in example embodiments, one ormore TRPs102 assigned to alogical entity110 transmit a DL synchronization signal in the sync channel using a pre-defined time and frequency (t/f) resource and frame structure.UE104, as part of its initial access procedure, searches for the synchronization signal. TheUE104 can search in the pre-defined t/f resources for a synchronization signal having the predefined frame structure. After synchronization is established, theUE104 can establish DL timing and frequency synchronization with thelogical entity110, and obtain an ID forlogical entity110. This information allowsUE104 to determine the correct PRACH t/f resources forUE104 to transmit a UL sequence to thelogical entity110. The logical entity can respond with a UL timing adjustment command to theUE104, thus allowing UL synchronization to be established with the network (Action304). Once DL and UL synchronization have been established, thenetwork controller106 can authenticateUE104 and assign: (a) a UE dedicated connection ID (UE DCID240); (b) an associated UE-centric sequence (UE SEQ242), which is a uniquely assigned ID sequence that the UE can transmit for low resource signaling in a tracking channel, such as a specific Zadoff-Chu sequence; (c) an uplink (UL) time/frequency (t/f) resource allocation for the tracking channel for the UE (UE TC T/F244); and (d) sounding resources including a UE-centric sounding reference signal (UE SRS246) and an uplink (UL) time/frequency resource allocation for a UL sounding channel (UE SC T/F248).UE SRS246 is an identifying signal that the UE can transmit for signaling to provide measurement information to the network in an UL sounding channel using the UL sounding channel time/frequency resource allocation UE SC T/F248.
• At the conclusion ofinitial access procedure210, theUE104 is provided with a Hypercell ID (i.e. an ID for logical entity110), a UE dedicated connection ID (UE DCID240), a UE-centric sequence (UE SEQ242), an uplink tracking resource allocation (UL TC T/F244), a UE-centric sounding reference signal (UE SRS246) and a sounding channel resource allocation UE SC T/F248). As will be explained in greater detail below and as illustrated inFIG. 2, theUE DCID240 is used across a number ofActive procedures208,ECO procedures206 andcommon procedures207. In example embodiments, the UE sequence (UE SEQ242) and Uplink tracking channel resource (UL TC T/F244) assignments are used primarily in theECO state202, and the UE sounding reference signal (UE SRS246) assignment and sounding channel resource (UE SC T/F248) assignments are used primarily in theActive state204. In some embodiments, the UE sequence (UE SEQ242) and Uplink tracking channel resource (UL TC T/F244) assignments are used exclusively in theECO state202, and the UE sounding reference signal (UE SRS246) and sounding channel resource (UE SC T/F248) assignments are used exclusively in theActive state204.
• As noted above, a grant-free transmission procedure212 can be supported in bothActive state204 andECO state202. Such a procedure may, for example, be useful for small packet transmissions with low dynamic signaling overhead. Thecontroller106 identifies or determines the traffic types that are suitable for grant-free transmission.FIGS. 4, 5, 6, and 7 illustrate a set of functions that are part of grant-free transmission procedure212. Aspects of suitable grant-free transmission procedures are described in detail in one or more of the aforementioned documents—see for example U.S. patent application Ser. No. 13/911,716 filed Jun. 6, 2013 (publication number US 2014/0192767 A1), entitled “System and Method for Small Traffic Transmissions” and U.S. patent application Ser. No. 13/790,673 filed Mar. 8, 2013, (publication number US 2014/0254544 A1) entitled “System and Method for Uplink Grant-Free Transmission Scheme”. Accordingly, FIGS.4-7 and the accompanying description provide a high level overview. In example embodiments, theUE DCID240 is used in both grant-free uplink and downlink communications to identify the target UE104 (in the case of a downlink transmission) or identify the sending UE (in the case of an uplink transmission). A shared grant-free uplink data channel and a shared grant-free downlink data channel can be used by multiple UEs, each of which may be in an Active state or an ECO state, to communicate with anetwork entity110.
• FIG. 4 illustratesnetwork side actions212A-UL enabled by the controller108 for grant-free UL transmissions, including the following:logical entities110 broadcast information about radio resources for UL grant-free transmission channel (“UL grant-free shared channel”) (Action401);controller106/logical entities110 perform blind detection on received data in UL grant-free transmission channel (Action402); andcontroller106 sends an acknowledgement message (ACK) throughlogical entity110 toUE104 upon successful data decoding (Action403).
• FIG. 5 illustrates the corresponding UE-side actions212B-UL performed byUE104 for UL grant-free transmissions, including:UE104 performs capability exchange for configuring UL grant-free transmission mode (Action501);UE104 derives grant-free resource mapping based on broadcast information (Action502); UE sends data (with a device identifier such as UE DCID240) in pre-defined resources with pre-configured modulation and coding scheme (MCS) (Action503); and UE may retransmit upon determination that the initial transmission failed, for example upon ACK timer expiry (Action504).
• FIG. 6 illustratesnetwork side actions212A-DL enabled by the controller108 for DL grant-free transmissions, including the following:logical entities110 broadcast information about DL grant-free transmission channel (“DL grant-free shared channel”) (Action601);controller106/logical entities110 send data in pre-defined resources with pre-configured MCS (Action602) (with target device identifier such asUE DCID240 in the case of a downlink for a specified UE); andcontroller106 may retransmit upon ACK timer expiry (Action603).
• FIG. 7 illustrates the corresponding UE-side actions212B-DL performed byUE104 for DL grant-free transmissions, including:UE104 performs capability exchange for configuring DL grant-free transmission mode (Action701);UE104 derives grant-free resource mapping based on broadcast information (Action702);UE104 performs blind detection on received data in DL grant-free transmission channel (Action703); andUE104 sends ACK upon successful data decoding (Action704).
• As noted above, in example embodiments ScheduledTransmission Procedures214 are only supported in the UEActive state204.FIGS. 8 and 9 respectively illustrate UE functions214-UL and214-DL that are performed byUE104 for uplink and downlink communications, respectively, as part of ScheduledTransmission Procedures214. Scheduled transmission procedures are described in one or more of the documents identified above, and accordinglyFIGS. 8 and 9 provide a summary. In an example embodiment, UL scheduled transmission occurs in an adaptive frame structure with filtered orthogonal frequency division multiplexing (f-OFDM), and UL grant information is sent via a control channel optimized to serve theUE104. AtUE104, UL scheduled transmission includes the following actions:UE104 sends scheduling request in the UL control channel in a configured UE UL frame structure (Action801);UE104 blindly decodes UE-centric grant control channel in the sub-band(s) of the configured DL frame structure(s) (Action802); and UE transmits data in the granted resource of UL shared data channel of the configured UE UL frame structure (Action803).
• DL scheduled transmission also occurs in an adaptive frame structure with f-OFDM. DL grant information is sent via a UE-centric control channel optimized to serve the UE. As illustrated inFIG. 9, atUE104, DL scheduled transmission includes the following actions:UE104 blindly decodes UE-centric DL control channel in the sub-band(s) of the configured UE DL frame structure(s) (Action990); andUE104 decodes data in the corresponding DL shared data channel in the corresponding DL frame structure (Action991).
• As noted above, in at least some embodiments Network-Oriented Measurement Procedures216 are supported exclusively inActive state204. Such procedures enable thecontroller106 to dynamically and flexibly configure servingTRPs102 for theUE104. Aspects of suitable Network-Oriented Measurement Procedures216 are described in detail in U.S. patent application Ser. No. 13/930,908 filed Jun. 28, 2013 (publication number US 2015/0003236 A1), entitled “System and Method for Network Uplink Measurement Based Operation Using UE Centric Sounding”.FIG. 10 provides a summary of Network-Oriented Measurement Procedures216, according to an example embodiment.UE104 is assigned UE centric sounding reference signal (UE SRS)246 and sounding radio resources UE SC T/F248 upon initial access (Action1001). In particular, this action is done as part of previously described Action306 (FIG. 3) duringinitial access procedure210. As part of Network-Oriented Measurement Procedure216, UE soundingsignals UE SRS246 are received by multiple nearby transmit points (TPs)102. DL and UL transmissions can be assisted by the UL measurements, and DL feedback requirements can be reduced. In this regard, as shown inFIG. 10,procedure216 includes:Controller106 configures UE-centric SRS (UE SRS246) and channel resources (UE SC T/F248) based on assigned UE dedicated connection ID andUE104 location (Action1001);TRPs102 detect and monitor UE centric SRS UE SRS246 (Action1002—performed on an ongoing basis);TRPs102 report measurement information forUEs104 to a controller106 (Action1003);controller106 generates and maintains UE-TRP association table (action1004); andcontroller106 determines thebest serving TRPs102 forUE104 based on the UE-TRP association table. Action1001 is performed as part of UE initial access;Actions1001,1003,1004 and1005 are performed by thenetwork controller106 on an ongoing basis for active-state UEs.
• In some example embodiments,UE104 is configured to transmit sounding resource signallingUE SRS246 using the sounding channel resources UE SC T/F248 exclusively while inActive state202. However, in some example embodiments,UE106 may provide the signalling required to support themeasurement procedures216 even in theECO state202.
• FIGS. 11 and 12 respectively illustrate a network initiated ECO to Activestate transition procedure218A and a UE initiated ECO to Activestate transition procedure218B. Examples of state transition procedures are described in detail in one or more of the documents identified above. In the illustrated example, state transition is contention free and uses a UE-centric sequence to reduce latency of the state transition.
• In an example embodiment, network-initiatedstate transition procedure218A from ECO to Active is triggered by a message from the network to theUE104, while theUE104 is in the ECO state, indicating that the network has downlink data to send to theUE104. Such a notification may, for example, occur when the amount of downlink data exceeds the data that could efficiently be sent in a grant-free shared channel. In this regard, in example embodiments,wireless communications network100 includes a low resource shared DL notification channel that can be used to send DL or paging notifications toUEs104. In some embodiments,UE104 could be informed of a DL notification channel assignment as part of theinitial access procedure210; alternatively, DL notification channel assignment could occur when aUE104 goes into an ECO state; alternatively, DL notification channel assignment could be done as part of UE factory provisioning or at other times.
• As shown inFIG. 11, in an example embodiment network-initiatedstate transition procedure218A from ECO to Active includes Actions1101-1105 performed atUE104 and Actions1111-1113 performed by networklogical element110 andnetwork controller106, as follows.UE104 monitors the DL notification channel for a paging/DL data notification while theUE104 is in ECO state (Action1101). When thenetwork controller106 determines that it has downlink data forUE104 that exceeds the capacity of the DL grant-free shared channel, thenetwork controller106 causes networklogical element110 to send a notification forUE104 in the DL notification channel (Action1111). In an example embodiment, the notification is addressed to theUE104 using the UE DCID240 (or an associated UE identifier that is a subset of the UE DCID such as the UE ID), and includes an indication that a transition to an Active state is required. In some embodiments, a flag or bit in the message could be set to indicate a state transition is required; in other examples, the indication is implicit in the message.UE104 receives the paging/DL data notification message indicating state transition (Action1102), andUE104 sends UE-centric sequence (UE SEQ242) to networklogical element110 for measurement purposes using a defined UL resource (Action1103). In some embodiments, theUE SEQ242 is sent in the UL tracking channel used intracking procedure222, discussed below. In some embodiments, theUE SEQ242 transmission is sent specifically in response to the DL data notification messages, however in someembodiments UE SEQ242 transmission is periodically sent as a tracking message to the network entity byUE104 during the time theUE104 is in the ECO state.
• One or more TRPs in thelogical entity110 receives theUE SEQ242 transmission.Network controller106 uses the information (for example the signal strength) from the received UE SEQ signal to confirm the network resources available to be dedicated to send the downlink data, and causes a further message to be sent toUE104 confirming that the transition to Active state should proceed (Action1112);UE104 receives the response from network logical element110 (Action1104) and thenUE104 transitions to Active state (Action1105). Data downlink procedure214-DL can then be implemented (Action1113).
• As shown inFIG. 12, UE-initiatedstate transition procedure218B from ECO to Active includes the following: UE sends UE-centricsequence UE SEQ242 to network logical element110 (Action1201); UE receives response from network logical element110 (Action1202); and UE transitions to Active state (Action1203).
• FIG. 13 illustratesstate transition procedure220 for moving from a UEActive state204 to aUE ECO state202. The Active to ECO state transition can be triggered by an activity timer expiry UE104 (procedure1301) or can be network initiated for other reasons (procedure1302). In the case oftimer expiry procedure1301, the following actions are taken in example embodiments:Network controller106 keeps track of a UE activity timer (Action1310); UE activity timer expires due to no data exchange (Action1312);Controller106 causes network to send to theUE104 via higher layer signaling (for example in the control layer) an instruction to transition to ECO state (Action1314).
• Inprocedure1302, thenetwork controller106 proactively initiates the UE transition to the ECO state (Action1316), and sends an instruction to transition to ECO state to theUE104 via higher layer signaling (for example in the radio resource control (RRC) layer) (Action1318).
• As noted above, in example embodiments, trackingprocedure222 is performed exclusively in theECO state202. A suitable tracking procedure is described in detail in the document mentioned above entitled: “System and Method for a Tracking Channel” (U.S. patent application Ser. No. 15/009,626 filed Jan. 28, 2016). Thetracking procedure222 in ECO state enables monitoring ofUEs104 bycontroller106 and in at least some examples uses less network t/f resources than are used in the active state network-orientedmeasurement procedure216 discussed above. Among other things, such ECO state tracking may, in at least some applications, provide one or more of the following features: facilitate a contention-free procedure with UE centric sequence, shorten response time by eliminating the contention resolution and RNTI assignment, and increase the capacity of random access by avoiding collision. As noted above, during the initial access procedure, a UE-centric sequence (UE SEQ242) is assigned toUE104 and a UL tracking channel resource (UL TC T/F244) is also assigned toUE104. These assigned characteristics are used byUE104 and the network for trackingprocedure222. In this regard,FIG. 14 provides a summary oftracking procedure222, which includes the following actions: Network controller106 (re-)configures UE centric sequence (UE SEQ242) and tracking channel resources (UL TC T/F244) and periodicity based on UE types and mobility information (Action1401);UE104 sends UE centric sequence (UE SES242) to the network (logical entity110) in a contention-free manner using the assigned tracking channel resources (Action1402); and UE receives response from the network (logical entity110).
• As noted above, in example embodiments, DLdata notification procedure224 is performed exclusively in theECO state202. A suitable DLdata notification procedure224 is described in detail in the document mentioned above entitled: “Apparatus And Method For a Wireless Device To Receive Data in an Eco State”. DLdata notification procedure224 provides a UE-specific notification (indication) of pending DL data transmission when the UE is in the “ECO”state202, and can be used to facilitate DL data transmission in the ECO state using the grant-free transmission procedure212 (such that no dynamic resource allocation is required). This can enable a reduced set of radio resources (reserved, pre-configured) for data transmission.FIG. 15 provides a summary of DLData notification procedure224, which includes the following actions in an example embodiment: in ECO state,UE104 monitors DL data notification (Action1501); optionally, UE sends additional measurements (1502); within a defined time duration, the UE expects to receive DL data while in the ECO state, over a grant-free DL channel (Action1503).
• As noted above,deregistration procedure226 is supported in both UE states in example embodiments. Deregistration can be triggered by events such as UE power off, or occurrence of a registration timer expiry. A registration timer expiry may, for example, occur on the network side when no data activities such astracking procedure222 occur for a predetermined time duration or at the UE side whenUE104 does not receive responses from the network for a predetermined duration.FIG. 16A illustrates a summary of a power off deregistration procedure, which is initiated whenUE104 sends a deregistration message to thenetwork entity110 as part of a power off procedure (Action1602). Thecontroller106 deregisters UE in response to the deregistration message (Action1604).FIG. 16B illustrates a registration timer expiry deregistration procedure, which is initiated when a registration timer expires at either the network or UE (Action1606), resulting in thecontroller106 deregistering the UE (Action1608).
• FIG. 17 is a block diagram of aprocessing system900 that may be used for implementing the UE and network devices and methods disclosed herein. Specific devices may utilize all of the components shown, or only a subset of the components and levels of integration may vary from device to device. Furthermore, a device may contain multiple instances of a component, such as multiple processing units, processors, memories, transmitters, receivers, etc. Theprocessing system900 may comprise aprocessing unit901 equipped with one or more input/output devices, such as a speaker, microphone, mouse, touchscreen, keypad, keyboard, printer, display, and the like. Theprocessing unit901 may include a central processing unit (CPU)910,memory920, amass storage device930, anetwork interface950, an I/O interface960, and anantenna circuit970 connected to abus940. Theprocessing unit901 also includes anantenna element975 connected to the antenna circuit.
• Thebus940 may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus, video bus, or the like. TheCPU910 may comprise any type of electronic data processor. Thememory920 may comprise any type of system memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), a combination thereof, or the like. In an embodiment, thememory920 may include ROM for use at boot-up, and DRAM for program and data storage for use while executing programs.
• Themass storage device930 may comprise any type of storage device configured to store data, programs, and other information and to make the data, programs, and other information accessible via thebus940. Themass storage device930 may comprise, for example, one or more of a solid state drive, hard disk drive, a magnetic disk drive, an optical disk drive, or the like.
• The I/O interface960 may provide interfaces to couple external input and output devices to theprocessing unit901. The I/O interface960 may include a video adapter. Examples of input and output devices may include a display coupled to the video adapter and a mouse/keyboard/printer coupled to the I/O interface. Other devices may be coupled to theprocessing unit901 and additional or fewer interface cards may be utilized. For example, a serial interface such as Universal Serial Bus (USB) (not shown) may be used to provide an interface for a printer.
• Theantenna circuit970 andantenna element975 may allow theprocessing unit901 to communicate with remote units via a network. In an embodiment, theantenna circuit970 andantenna element975 provide access to a wireless wide area network (WAN) and/or to a cellular network, such as Long Term Evolution (LTE), Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), and Global System for Mobile Communications (GSM) networks. In some embodiments, theantenna circuit970 andantenna element975 may also provide Bluetooth and/or WiFi connection to other devices.
• Theprocessing unit901 may also include one ormore network interfaces950, which may comprise wired links, such as an Ethernet cable or the like, and/or wireless links to access nodes or different networks. Thenetwork interface901 allows theprocessing unit901 to communicate with remote units via thenetworks980. For example, thenetwork interface950 may provide wireless communication via one or more transmitters/transmit antennas and one or more receivers/receive antennas. In an embodiment, theprocessing unit901 is coupled to a local-area network or a wide-area network for data processing and communications with remote devices, such as other processing units, the Internet, remote storage facilities, or the like.
• Although the present disclosure describes methods and processes with steps in a certain order, one or more steps of the methods and processes may be omitted or altered as appropriate. One or more steps may take place in an order other than that in which they are described, as appropriate.
• While the present disclosure is described, at least in part, in terms of methods, a person of ordinary skill in the art will understand that the present disclosure is also directed to the various components for performing at least some of the aspects and features of the described methods, be it by way of hardware components, software or any combination of the two. Accordingly, the technical solution of the present disclosure may be embodied in the form of a software product. A suitable software product may be stored in a pre-recorded storage device or other similar non-volatile or non-transitory computer readable medium, including DVDs, CD-ROMs, USB flash disk, a removable hard disk, or other storage media, for example. The software product includes instructions tangibly stored thereon that enable a processing device (e.g., a personal computer, a server, or a network device) to execute examples of the methods disclosed herein. In example embodiments, theUE104,TRPs102 andnetwork controller106 each comprise amemory920 tangibly storing executable instructions that, when executed byCPU910 to cause theUE104, TP102 ornetwork controller106 to perform the functions and procedures described above.
• The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. The described example embodiments are to be considered in all respects as being only illustrative and not restrictive. Selected features from one or more of the above-described embodiments may be combined to create alternative embodiments not explicitly described, features suitable for such combinations being understood within the scope of this disclosure.
• All values and sub-ranges within disclosed ranges are also disclosed. Also, while the systems, devices and processes disclosed and shown herein may comprise a specific number of elements/components, the systems, devices and assemblies could be modified to include additional or fewer of such elements/components. For example, while any of the elements/components disclosed may be referenced as being singular, the embodiments disclosed herein could be modified to include a plurality of such elements/components. The subject matter described herein intends to cover and embrace all suitable changes in technology.

Claims (25)

1. A method comprising:

assigning, by a network controller, a user equipment (UE) centric sequence and a tracking channel resource to a UE that is in a first state, the first state being different from an active state; and

providing, by the network controller, the assigned UE centric sequence and the tracking channel resource to the UE.

2. The method according toclaim 1, wherein the UE centric sequence and the tracking channel resource are assigned by a network controller based on a type of the UE and mobility information of the UE.

3. The method according toclaim 1, wherein the UE centric sequence is a uniquely assigned ID sequence to be transmitted in a tracking channel by the UE that is in the first state.

4. The method according toclaim 1, wherein the UE centric sequence is a specific Zadoff-Chu sequence.

5. The method according toclaim 1, wherein the tracking channel resource is an uplink time and frequency resource allocated for the tracking channel for the UE.

6. The method according toclaim 1, further comprising:

assigning, by the network controller, information associated with a periodicity based on UE types and mobility information; and

providing, by the network controller, the periodicity to the UE that is in the first state.

7. The method according toclaim 1, wherein the assigned UE centric sequence and the assigned tracking channel resource are provided to the UE that is in the first state during an initial access procedure of the UE.

8. The method according toclaim 1, further comprising:

monitoring, by the network controller, the UE's tracking during the time the UE is in the first state.

9. The method according toclaim 1, wherein the first state is characterized by one or more of: supporting a reduced set of UE functionality that the active state supports; or requiring less network resource compared to the active state.

10. The method according toclaim 1, wherein the state supports a data transfer connectivity without dynamic resource allocation request and grant from the network node.

11. The method according toclaim 1, wherein the tracking channel resource is provided to the UE for tracking the UE that is in the first state.

12. An apparatus comprising a processor coupled with a memory, the processor configured to:

assign a user equipment (UE) centric sequence and a tracking channel resource to a UE that is in a first state, the first state being different from an active state; and

provide the assigned UE centric sequence and the tracking channel resource to the UE.

13. A method comprising:

receiving, from a network entity, by a user equipment (UE) that is in a first state, a UE centric sequence and a tracking channel resource; and

sending, to the network entity, by the UE that is in the first state, the UE centric sequence on the tracking channel resource, the first state being different from an active state.

14. The method according toclaim 13, wherein the UE centric sequence and the tracking channel resource are assigned based on a type of the UE and mobility information of the UE.

15. The method according toclaim 13, wherein the UE centric sequence is a uniquely assigned ID sequence to be transmitted by the UE that is in the first state in a tracking channel.

16. The method according toclaim 13, wherein the UE centric sequence is a specific Zadoff-Chu sequence.

17. The method according toclaim 13, wherein the tracking channel resource is an uplink time and frequency resource allocated for the tracking channel for the UE.

18. The method according toclaim 13, wherein the UE centric sequence on the tracking channel resource is sent, by the UE that is in the first state, according to an assigned periodicity.

19. The method according toclaim 18, further comprising:

receiving, by the UE that is in the first state, information associated with the periodicity.

20. The method according toclaim 13, wherein the UE centric sequence on the tracking channel resource is sent, by the UE that is in the first state to the network entity, in a contention-free manner.

21. The method according toclaim 20, further comprising, after sending the UE centric sequence on the tracking channel resource:

receiving, by the UE that is in the first state a response from the network entity.

22. The method according toclaim 13, wherein the UE centric sequence and the tracking channel resource are received by the UE during an initial access procedure of the UE.

23. The method according toclaim 13, wherein the first state is characterized by one or more of: supporting a reduced set of UE functionality that the active state supports; or requiring less network resource compared to the active state.

24. The method according toclaim 13, wherein the state supports a data transfer connectivity without dynamic resource allocation request and grant from the network node.

25. An apparatus comprising a processor coupled with a memory, the processor configured to:

when the apparatus is in a first state, receive a user equipment (UE) centric sequence and a tracking channel resource from a network entity and send to the network entity the UE centric sequence on the tracking channel resource, the first state being different from an active state.

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